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KVM: Enforce error in ioctl for compat tasks when !KVM_COMPAT 

The current behaviour of the compat ioctls is a bit odd.
We provide a compat_ioctl method when KVM_COMPAT is set, and NULL
otherwise. But NULL means that the normal, non-compat ioctl should
be used directly for compat tasks, and there is no way to actually
prevent a compat task from issueing KVM ioctls.

This patch changes this behaviour, by always registering a compat_ioctl
method, even if KVM_COMPAT is not selected. In that case, the callback
will always return -EINVAL.

Fixes: de8e5d7440 ("KVM: Disable compat ioctl for s390")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier 2018-06-17 10:16:21 +01:00
parent 47a91b7232
commit 7ddfd3e0df
1 changed files with 9 additions and 10 deletions
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19
virt/kvm/kvm_main.c
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@ -116,6 +116,11 @@ static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#define KVM_COMPAT(c) .compat_ioctl = (c)
#else
static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg) { return -EINVAL; }
#define KVM_COMPAT(c) .compat_ioctl = kvm_no_compat_ioctl
#endif
static int hardware_enable_all(void);
static void hardware_disable_all(void);
@ -2396,11 +2401,9 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp)
static struct file_operations kvm_vcpu_fops = {
.release = kvm_vcpu_release,
.unlocked_ioctl = kvm_vcpu_ioctl,
#ifdef CONFIG_KVM_COMPAT
.compat_ioctl = kvm_vcpu_compat_ioctl,
#endif
.mmap = kvm_vcpu_mmap,
.llseek = noop_llseek,
KVM_COMPAT(kvm_vcpu_compat_ioctl),
};
/*
@ -2824,10 +2827,8 @@ static int kvm_device_release(struct inode *inode, struct file *filp)
static const struct file_operations kvm_device_fops = {
.unlocked_ioctl = kvm_device_ioctl,
#ifdef CONFIG_KVM_COMPAT
.compat_ioctl = kvm_device_ioctl,
#endif
.release = kvm_device_release,
KVM_COMPAT(kvm_device_ioctl),
};
struct kvm_device *kvm_device_from_filp(struct file *filp)
@ -3165,10 +3166,8 @@ static long kvm_vm_compat_ioctl(struct file *filp,
static struct file_operations kvm_vm_fops = {
.release = kvm_vm_release,
.unlocked_ioctl = kvm_vm_ioctl,
#ifdef CONFIG_KVM_COMPAT
.compat_ioctl = kvm_vm_compat_ioctl,
#endif
.llseek = noop_llseek,
KVM_COMPAT(kvm_vm_compat_ioctl),
};
static int kvm_dev_ioctl_create_vm(unsigned long type)
@ -3259,8 +3258,8 @@ static long kvm_dev_ioctl(struct file *filp,
static struct file_operations kvm_chardev_ops = {
.unlocked_ioctl = kvm_dev_ioctl,
.compat_ioctl = kvm_dev_ioctl,
.llseek = noop_llseek,
KVM_COMPAT(kvm_dev_ioctl),
};
static struct miscdevice kvm_dev = {